Columnar Basalt Layers
Over a period of 20 million years, giant fissures would split open the earth in eastern Washington, time after time spewing molten lava over tens of thousands of square miles, creating multiple layers of now dried and cracked basalt rock. So many layers that, in some places, there are over 10,000 feet of them. Each layer is about 75 to 100 feet thick, a few of which can be seen above near the Potholes Reservoir. These lava beds extend over eastern Washington between 3 rivers, the Spokane, Columbia and the Snake, and into parts of Idaho and Oregon. Then, about 10,000 years ago, at the end of the last ice age, huge lakes of melt water were dammed up by arms of a glacier, which eventually melted, and this huge amount of water roared over the basalt beds, carving, tearing and gouging as it went, creating the Channeled Scablands visible today. The geology of eastern Washington is unique and well worth studying, and even better, visiting in person!
Columnar Basalt Layers
Over a period of 20 million years, giant fissures would split open the earth in eastern Washington, time after time spewing molten lava over tens of thousands of square miles, creating multiple layers of now dried and cracked basalt rock. So many layers that, in some places, there are over 10,000 feet of them. Each layer is about 75 to 100 feet thick, a few of which can be seen above near the Potholes Reservoir. These lava beds extend over eastern Washington between 3 rivers, the Spokane, Columbia and the Snake, and into parts of Idaho and Oregon. Then, about 10,000 years ago, at the end of the last ice age, huge lakes of melt water were dammed up by arms of a glacier, which eventually melted, and this huge amount of water roared over the basalt beds, carving, tearing and gouging as it went, creating the Channeled Scablands visible today. The geology of eastern Washington is unique and well worth studying, and even better, visiting in person!